public class Test {
	public static void main (String [] args){
		A a1 = new A();
		A a2 = new B();
		B b = new B();
		C c = new C();
		D d = new D();

		System.out.println ("1--" + a1.show(b));
		System.out.println ("2--" + a1.show(c));
		System.out.println ("3--" + a1.show(d));
		System.out.println ("4--" + a2.show(b));
		System.out.println ("5--" + a2.show(c));
		System.out.println ("6--" + a2.show(d));
		System.out.println ("7--" + b.show(b));
		System.out.println ("8--" + b.show(c));
		System.out.println ("9--" + b.show(d));
	}
}
